Combination gear and vane pump



Fell 1967 G. H. DRUTCHAS COMBINATION GEAR AND VANE PUMP Filed Aug. 20, 1965 &

F-E-Z INVENTOR. 6/ seer 0207-0445 By ATTORNEYS United States Patent 3,306,228 COMBINATION GEAR AND VANE PUMP Gilbert H. Drutchas, Birmingham, Mich., assignor to TRW Inc., Cleveland, Ohio, a corporation of Ohio Filed Aug. 20, 1965, Ser. No. 481,248 1 Claim. (Cl. 103-126) This invention relates generally to pumps and more particularly relates to a double external gear, double eccentric vane pump wherein three distint pumping actions are available in a single pump through the utilization of a normal double external pump form wherein two intermeshing gear members positively displace fluid from between respective tooth spaces and simultaneously two additional pumping actions occur by the utilization of vane means carried by each respective gear and sweeping an expansible chamber provided by an offset casing contour outwardly'adjacent each respective gear.

It is an object of the present invention to combine in a single pump a double external gear pumping action and a double eccentric vane pumping action.

Yet another object of the present invention is to provide a pump assembly wherein three distinct pumping actions will take place in a single unit.

Still another object-of the present invention is to provide a combination gear and vane pump wherein the utilization of vane sealing removes the problemof tip clearance.

A still further object of the present invention is to provide a multiple pump utilizing rotary gears wherein hydraulic unbalance acting on the gears is reduced, thereby easing bearing loads.

Many other features and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description which follows and the accompanying sheets of drawings in which a preferred embodiment of a pump incorporating the principles of the present invention is shown by way of illustrative example.

On the drawings:

FIGURE 1 is a cross-sectional view showing a double external gear, double eccentric vane pump incorporating the principles of the present invention; and

FIGURE 2 is a fragmentary cross-sectional view taken generally on line IIII of FIGURE 1.

As shown on the drawings:

The combination gear and vane pump of the present invention is shown generally at and comprises a casing shown generally at 11 and consisting of three parts including side headers 12 and 13 disposed on opposite sides of a housing member 14. The housing member is formed with an inlet 16 formed in a boss 17 projecting outwardly at one side of the housing 14 and is further provided with an outlet 18 formed in a boss 19 projecting from the opposite side of the housing 14.

Internally, the housing is particularly characterized by the formation therein of a pumping chamber herein taking the form of a double-lobed pumping cavity including a first lobe 20 and a second lobe 21.

A pair of pumping rotors 22 and 23 are rotatably journaled in the casing 11 and are carried by shaft members shown respectively at 24 and 26. It will be understood that one or the other of the shafts 24 or 26 may be connected to a suitable source of rotative power, thereby to rotatably drive the rotors 22 and 23.

The shafts 24 and 26 are disposed on axes of rotation which are concentric with respect to the bore walls of the lobe 20 and the lobe 21 and each respective rotor is particularly characterized by the formation in the peripheral surface thereof of alternating gear teeth 27 and gear tooth spaces 28. Thus, the rotors 22 and 23 are in 3,306,228 Patented Feb. 28, 1967 full meshing engagement at an area of intermesh disposed between the inlet 16 and the outlet 18.

In accordance with the principles of the present invention, the housing 14 is particularly characterized by an offset casing contour shown at 29 in connection with the lobe and at 30 in connection with the lobe 21. In each instance, the casing contour is disposed eccentrically out wardly of each respective rotor 22 and 23, thereby to form a crescent-shaped working chamber 31 and 32, respectively, or, in other words, an expansible chamber.

Each rotor 22 and 23 is characterized -by the provision of slidingvane means, thereby to effect an additional pumping action which is completely independent of the normal double external pump form resulting from the gear intermesh. In this particular embodiment, the rotor 22 is shown equipped with four peripheral slots 33 which are spaced circumferentially from one another and which are disposed between the alternating gear teeth and gear tooth spaces 27 and 28. Likewise, the rotor 23 is provided with four circumferentially spaced peripheral slots i 34. Each slot 33 slidably carries an appropriate vane herein shown as constituting a roller-type vane 36. The vanes in the rotor 23 are shown at 37 and are correspondingly located in the slots 34.

In order to communicate each respective working chamber 31 and 32 with the inlet 16, the housing 14 is formed with radial ports shown at 38 and 39, respectively, on the inlet side, and at 40 and 41, on the outlet side.

The operation of the pump assembly consists of three distinct pumping actions. The first pumping action consists of the normal double external pump form wherein the two rotary gears 22 and 23 plunge their respective tooth spaces in the area of intermesh, thereby affording a positive displacement pumping action. In this form of pumping action, it will be understood that the rotor gears 22 and 23 are rotated in the direction of the arrows and the spaces between the teeth 28 are filled with fluid in the inlet 16 whereupon the fluid is carried externally until the teeth 27 displace the fluid out of the spaces 28 and the fluid is discharged from the outlet 18 under increased pressure.

Simultaneously, there exist two additional pumping actions which occurs due to the oifset casing contour and the vane means carried by the rotors 22 and 23. Flow in the inlet passage 16 enters and separates through the radial ports 38 and 39 to fill the opening cavities behind the roller vanes 36 and 37 shown positioned in near register with the radial ports 38 and 39 in FIGURE 1 of the drawings. When that roller vane moves to a point beyond the radial port, either 38 or 39, the fluid is contained within a sealed working arc from where the fluid is pumped into the outlet passage 18 from each respective section of vane action.

In the exemplary illustration, a single inlet passage 16 and a single outlet passage 18 are provided. Thus, the radial ports 38 and 39 have cut-off points shown at 38a and 39a. It will be readily understood that a separate porting means could be provided for the working chambers 31 and 32, if desired so that the pump of the present invention could not only be utilized to develop three separate pumping actions, but such pumping actions could actually be made independent through the utilization of separate portingf Moreover, the arrangement disclosed permits staging of gear pumps in a single gear pump unit. By virtue of the vane sealing, tip clearance is avoided as a problem and hydraulic unbalance on the rotor gears is reduced, thereby easing bearing loads.

Lastly, by terminating the outlets of the two vane motions, the valve pumps may be used as motors to motor the double external gear pump.

Although other forms of sliding vanes may be used, the advantage of using cylindrical vanes such as the vanes 36 and 37 herein shown include the provision of cylindrical members which are easily fabricated, readily slidable and which will be urged out of their respective slots by the action of centrifugal force and do not require additional mounting even when in their outermost positions.

Although minor modifications might be suggested by those versed in the art, it should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the alt.

I claim as my invention:

A pump comprising a housing having an inlet and an outlet at opposite sides thereof,

said housing having formed internally thereof between said inlet and said outlet at double-lobed pumping cavity including first and second lobes disposed relatively transversely of said inlet and said outlet,

a pair of pumping rotors in said housing having shaft means disposed on axes of rotation concentric to the bore walls of said first and second lobes,

each rotor having alternating gear teeth and gear tooth spaces and being in full meshing engagement with .one another,

said housing having an offset casing contour disposed eccentrically outwardly of each respective rotor to form a crescent-shaped expansible working chamber in each respective lobe,

each rotor having a plurality of circumferentially spaced peripheral slots formed therein and disposed between the alternating gear teeth and gear tooth spaces,

References Cited by the Examiner UNITED STATES PATENTS 137,055 3/1873 Chapman 103-126 145,671 12/1873 Maxson 91123 345,885 7/1886 Colebrook 103-136 563,623 7/1896 Shedd 91-87 931,900 8/1909 Tompkins 230-141 1,436,263 11/ 1922 Johnson 230141 2,588,342 3/1952 Bidwell 91123 2,657,638 11/1953 English 103136 FOREIGN PATENTS 1,350,628 12/1963 France.

30 DONLEY J. STOCKING, Primary Examiner.

WILBUR J. GOODLIN, Examiner. 

